Improving awareness and accessibility of healthy diets are key challenges for health professionals and policymakers alike. While the US government has been assessing and encouraging nutritious diets via the Dietary Guidelines for Americans (DGA) since 1980, the long-term sustainability, and thus availability, of those diets has received less attention. The 2015 Dietary Guidelines Advisory Committee (DGAC) examined the evidence on sustainable diets for the first time, but this topic was not included within the scope of work for the 2020 DGAC. The objective of this study was to systematically review the evidence on US dietary patterns and sustainability outcomes published from 2015 to 2019 replicating the 2015 DGAC methodology. The 22 studies meeting inclusion criteria reveal a rapid expansion of research on US dietary patterns and sustainability, including 8 studies comparing the sustainability of DGA-compliant dietary patterns with current US diets. Our results challenge prior findings that diets adhering to national dietary guidelines are more sustainable than current average diets and indicate that the Healthy US-style dietary pattern recommended by the DGA may lead to similar or increased greenhouse gas emissions, energy use, and water use compared with the current US diet. However, consistent with previous research, studies meeting inclusion criteria generally support the conclusion that, among healthy dietary patterns, those higher in plant-based foods and lower in animal-based foods would be beneficial for environmental sustainability. Additional research is needed to further evaluate ways to improve food system sustainability through both dietary shifts and agricultural practices in the United States.

Farmers in China's tea-growing regions report that monsoon dynamics and other weather factors are changing and that this is affecting tea harvest decisions. To assess the effect of climate change on tea production in China, this study uses historical weather and production data from 1980 to 2011 to construct a yield response model that estimates the partial effect of weather factors on tea yields in China, with a specific focus on East Asian Monsoon dynamics. Tea (Camellia sinensis (L.) Kunze) has not been studied using these methods even though it is an important crop for human nutrition and the economic well-being of rural communities in many countries. Previous studies have approximated the monsoon period using historical average onset and retreat dates, which we believe limits our understanding of how changing monsoon patterns affect crop productivity. In our analysis, we instead estimate the monsoon season across China's tea growing regions empirically by identifying the unknown breakpoints in the year-by-province cumulative precipitation. We find that a 1% increase in the monsoon retreat date is associated with 0.481%-0.535% reduction in tea yield. In the previous year, we also find that a 1% increase in the date of the monsoon retreat is associated with a 0.604% decrease in tea yields. For precipitation, we find that a 1% increase in average daily precipitation occurring during the monsoon period is associated with a 0.184%-0.262% reduction in tea yields. In addition, our models show that 1% increase in the average daily monsoon precipitation from the previous growing season is associated with 0.258%-0.327% decline in yields. We also find that a 1% decrease in solar radiation in the previous growing season is associated with 0.554%-0.864% decrease in tea yields. These findings suggest the need for adaptive management and harvesting strategies given climate change projections and the known negative association between excess rainfall and delayed monsoon retreat on tea quality and yield.

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ObjectiveTo determine if US household food purchases with lower levels of red meat spending generate lower life-cycle greenhouse gas emissions (GHGE), greater nutritional quality and improved alignment with the Dietary Guidelines for Americans. Affordability of purchasing patterns by red meat spending levels was also assessed.DesignHousehold food purchase and acquisition data were linked to an environmentally extended input–output life-cycle assessment model to calculate food GHGE. Households (n 4706) were assigned to quintiles by the share of weekly food spending on red meat. Average weekly kilojoule-adjusted GHGE, total food spending, nutrients purchased and 2010 Healthy Eating Index (HEI-2010) were evaluated using ANOVA and linear regression.SettingUSA.ParticipantsHouseholds participating in the 2012–2013 National Household Food Acquisition and Purchase Survey.ResultsThere was substantial variation in the share of the household food budget spent on red meat and total spending on red meat. The association between red meat spending share and total food spending was mixed. Lower red meat spending share was mostly advantageous from a nutritional perspective. Average GHGE were significantly lower and HEI-2010 scores were significantly higher for households spending the least on red meat as a share of total food spending.ConclusionsOnly very low levels of red meat spending as a share of total food spending had advantages for food affordability, lower GHGE, nutrients purchased and diet quality. Further studies assessing changes in GHGE and other environmental burdens, using more sophisticated analytical techniques and accounting for substitution towards non-red meat animal proteins, are needed.

Objectives: To evaluate the association between diet quality and cost for foods purchased for consumption at home and away from home. Design: Cross-sectional analysis. Multivariable linear regression models evaluated the association between diet quality and cost for all food, food at home, and food away from home. Setting: Daily food intake data from the National Health and Nutrition Examination Survey (2005-2016). Food prices were derived using data from multiple, publicly available databases. Diet quality was assessed using the Healthy Eating Index-2015 and the Alternative Healthy Eating Index-2010. Participants: 30,564 individuals ≥20 y with complete and reliable dietary data. Results: Mean per capita daily diet cost was $14.19 (95% CI: $13.91-14.48), including $6.92 ($6.73-7.10) for food consumed at home and $7.28 ($7.05-7.50) for food consumed away from home. Diet quality was higher for food at home compared to food away from home (P<0.001). Higher diet quality was associated with higher food costs overall, at home, and away from home (P<0.001 for all comparisons). Conclusions: These findings demonstrate that higher diet quality is associated with higher costs for all food, food consumed at home, and food consumed away from home. This research provides policymakers, public health professionals, and clinicians with information needed to support healthy eating habits. These findings are particularly relevant to contemporary health and economic concerns that have worsened because of the COVID-19 pandemic.

Objective:To compare federally reimbursable school meals served when competitive foods are removed and when marketing and nudging strategies are used in school cafeterias operating the National School Lunch Program (NSLP). The second objective was to determine how marketing and nudging strategies influence competitive food sales.Design:In the Healthy Choices School, all competitive foods were removed; the Healthy Nudging School retained competitive foods and promoted the school meal programme using marketing and nudging strategies; a third school made no changes. Cafeteria register data were collected from the beginning of the 2013–2014 school year through the four-week intervention. Outcome measures included daily entrées served; share of entrées served with vegetables, fruit and milk; and total competitive food sales. Difference-in-difference models were used to examine outcome measure changes.Setting:Three high schools in a diverse, Northeast US urban district with universally free meals.Participants:High-school students participating in the NSLP.Results:During the intervention weeks, the average number of entrées served daily was significantly higher in the Healthy Choices School (82·1 (se 33·9)) and the Healthy Nudging School (107·4 (se 28·2)) compared with the control school. The only significant change in meal component selection was a 6 % (se 0·02) higher rate of vegetable servings in the Healthy Choices School compared with the control school. Healthy Nudging School competitive food sales did not change.Conclusions:Both strategies – removing competitive foods and marketing and nudging – may increase school meal participation. There was no evidence that promoting school meals decreased competitive food sales.

BACKGROUND: This study tested the hypothesis that written district wellness policies are associated with higher rates of implementation of nutrition and physical activity practices. METHODS:Written wellness policies and building level practices were assessed for schools (N = 295) within high-need districts (N = 70) in New York State. The relationship between policies and practices was measured using multi-level mixed-effects logistic regressions. RESULTS:Overall, stronger written district policies significantly increase the likelihood of practice implementation in schools.This relationship is strongest for physical education and physical activity items, followed by nutrition standards for competitive foods in middle and high schools. Most elementary schools implemented nutrition practices with or without a policy and there were differences in implementation rates between elementary and middle/high schools. When examined separately, policies were for the most part not significantly associated with implementation of corresponding practices. CONCLUSIONS:Strong and comprehensive written policies are associated with higher rates of practice implementation overall, but the consistency of this relationship varies by policy-practice domain. The newer policy topics areas of school wellness promotion and marketing were less frequently included in written policies. Future research should examine whether districts that strengthen their written policies achieve greater implementation over time.

This article investigates the impact of the 2010 Patient Protection and Affordable Care Act (ACA) on the healthfulness of non-alcoholic beverage (NAB) choices of low-income households. A theoretical analysis proposes an income effect that increases unhealthy beverage purchases after Medicaid expansion and a nutrition education effect that decreases them. To empirically test these effects, we utilize household-level data for NAB purchases in 52 U.-S. metropolitan areas. Our identification strategy is based on eligible households following the 2012 Supreme Court ruling that allowed states to opt out of Medicaid expansion. We examine changes in purchases across NAB categories and in purchases at the product-brand level. Empirical results indicate that Medicaid expansion resulted in eligible households buying more diet carbonated soft drinks (CSDs) and bottled water, with no effect on regular CSDs, fruit juice, fruit drinks, milk, or tea. Moreover, the expansion led to decreases in sugar purchases and increases in purchases of NAB products with lower sugar content, highlighting the benefits of supplementing the medical benefits of Medicaid with diet quality programs, such as nutrition education.